


Calculating the Amount of Blood Senketsu Needs

by ArgentDandelion



Category: Kill la Kill (Anime & Manga)
Genre: Analysis, Blood, Blood Loss, Gen, Originally Posted on Tumblr
Language: English
Status: Completed
Published: 2015-10-10
Updated: 2015-10-10
Packaged: 2020-11-25 17:08:46
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 511
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/20915597
Author URL: https://archiveofourown.org/users/ArgentDandelion/pseuds/ArgentDandelion
Summary: Contains calculations on exactly how much blood Senketsu needs for transformation after episode 3 ("Junketsu") of Kill la Kill.





	Calculating the Amount of Blood Senketsu Needs

_Note: Though the article is for general audiences, Kill la Kill is itself PG-13 to R, due to blood, swearing, and nudity_.

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In episode 15, Senketsu makes a blade out of the claws of Senketsu Seijin. When cut by Satsuki’s sword Bakuzan, the blade spurts out blood onto Satsuki’s face, temporarily blinding her. He says: “I put all the blood I sucked into the blade. It was risky, but it worked.”

If it was truly _all_ the blood he sucked, and this was blood he took for the transformation to occur and not extra blood, then the amount of blood required for transformation at this point can be estimated by the splatter on Satsuki’s face. Whatever amount of blood required to recreate this splatter is the amount of blood he needs.

The easiest way to recreate this would be to paint some blood (real or fake) onto a face with the same proportions at Satsuki’s. However, I don’t have any blood, real or fake, on hand, nor do I have a Satsuki stand-in, so I’ll have to do back-of-the-envelope calculations.

I’m guessing it’s somewhere between 60 milliliters and 100 milliliters.

Is that a lot of blood relative to Ryuko’s total blood volume?

According to [Hatena Blog](https://t.umblr.com/redirect?z=http%3A%2F%2Fnbakki.hatenablog.com%2Fentry%2F2014%2F05%2F28%2F122924&t=OTM1MmM0NWRhMzZmMWNhODAxN2ViYTQyNDJkZWE4ZjQxOWQ0MWI1OCx2dm9PRnpHdg%3D%3D&b=t%3AHZZTbr56CX-Pu8cYzedJTw&p=https%3A%2F%2Fargentdandelion.tumblr.com%2Fpost%2F130925497121%2Fcalculating-the-amount-of-blood-senketsu-needs&m=1), the average weight of female students at Japanese high schools at age 17 is 52.3 kilograms. Using [this](https://t.umblr.com/redirect?z=http%3A%2F%2Freference.medscape.com%2Fcalculator%2Festimated-blood-volume&t=ODQwOGMzYjhhNTA0NjRjYWZiMzJhNmU1ZjI1NGQ0ODM1MzVmZTcxMSx2dm9PRnpHdg%3D%3D&b=t%3AHZZTbr56CX-Pu8cYzedJTw&p=https%3A%2F%2Fargentdandelion.tumblr.com%2Fpost%2F130925497121%2Fcalculating-the-amount-of-blood-senketsu-needs&m=1) blood volume estimation tool, entering the statistic “52.3 kg” brings the estimate of 3399.50 milliliters blood volume. Therefore, 100 milliliters is about 2.94 percentage of Ryuko’s total blood volume. (For comparison, a typical donation of blood is 450 to 500 milliliters.) If my estimate is correct, the amount of blood Senketsu takes at this point is perfectly safe, safer than a normal blood drawing, even. (And that’s already safe)

Let’s assume the blood splatter covers about one-fourth of Satsuki’s face. Entering 52.3 kilograms, female, 5 feet 3 inches into [this](https://t.umblr.com/redirect?z=http%3A%2F%2Fwww.calculator.net%2Fbody-surface-area-calculator.html%3Fcsex%3Dm%26bodyweight%3D52.3%26bodyweightunit%3Dkilogram%26bodyheightfeet%3D5%26bodyheightinch%3D3%26bodyheight%3D%26bodyheightunit%3Dmeter%26x%3D97%26y%3D10&t=ZjgzNjY3MzI2ZDA0NDg0MWE1ZGY1ODJmOGYyMTJkNGJhYWFiYWJiOSx2dm9PRnpHdg%3D%3D&b=t%3AHZZTbr56CX-Pu8cYzedJTw&p=https%3A%2F%2Fargentdandelion.tumblr.com%2Fpost%2F130925497121%2Fcalculating-the-amount-of-blood-senketsu-needs&m=1) calculator brings a calculated body surface area of 1.41 to 1.53 square meters.

Let’s say the surface area of the skin is 1.5 square meters, or 15,000 square cm. If the total skin-surface-area of the head is 9 percent (4.5 posterior head and 4.5 anterior head) of the body total, that’s 1,350 square centimeters. If the total surface area of the face is one-third that of the head, it’s 3 percent of 15,000, or 450 square centimeters. Let’s assume one-fourth of Satsuki’s face was covered in blood. One fourth (25 percent) of 3 percent is 0.75. 0.75 of 15,000 is 112.5 square cm. (112.5 cm feels wrong somehow, but I don’t know how to calculate a better estimate.)

So the amount of blood Senketsu takes is, very roughly, however much blood is required to cover 112.5 square cm. It’s a very rough calculation not only because we don’t know the exact proportions of Satsuki’s face and exactly how much of her face is covered by blood, but because not all of the blood sprayed landed on Satsuki’s face.

**Author's Note:**

> Originally posted on my [Tumblr](https://argentdandelion.tumblr.com/). Feel free to comment on this article there or here.


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